COUNTLESS FATHERS SEARCHED for wounded sons in the aftermath of Civil War battles. The Boston poet and physician Oliver Wendell Holmes sought out his wounded son, the future Supreme Court justice of the same name, not once but twice. In the elder Holmes’s account, published in the Atlantic Monthly in late 1862 after the battle at Antietam, the train to Maryland was packed with fathers seeking sons. In a war in which medical care was not far advanced beyond what it had been 100 or 200 years before, parents wanted desperately to rescue their young men from Civil War hospitals full of the wounded and the dying.
Most parents would barely have known where to begin their search, and Francis Lieber was no exception. Administrative chaos reigned in the new mass armies of the Union. On the eve of the war, some 16,367 officers and enlisted men served in the U.S. Army. Such numbers could not even begin to match the scale of the Civil War. In July 1861, the Congress authorized an army of half a million volunteers. By the end of the war, more than 2 million men would serve in a Union uniform and 1 million more would fight in the Confederate States Army. The infrastructure for these modern armies had barely been imagined, let alone put into place. Union wounded at Fort Donelson, for example, went to at least half a dozen different places, with no centralized information source or tracking mechanism for keeping records on who went where. And so when Francis Lieber went on his frantic search for Hamilton, he could not find him. (Later that year, Holmes the father would travel in circles for days before finding his son.) Hamilton was not at Cincinnati, where Francis went first. He went next to St. Louis, where he was directed on to Mound City. After ten days of walking through Union hospitals and peering into ambulances, Francis at last found Hamilton recuperating in a makeshift Union hospital. “I knew war as [a] soldier, as a wounded man in the hospital, as an observing citizen,” he told Sumner; but he had only now learned it as “a father searching for his wounded son.”
FRANCIS LIEBER’S ANXIOUS search produced a fortuitous reunion. Francis had almost forgotten, but on one of his usual summer trips to the North in July and August of 1845, he had dined regularly at the U.S. Army installation on Governors Island in New York Harbor. The main topic of conversation had been Charles Sumner’s controversial antiwar speech, which had been delivered only a few weeks before. Lieber’s dinner-table denunciations of Sumner and the peace societies had powerfully impressed a lieutenant of engineers named Henry Halleck. Now, seventeen years later, Halleck was stationed in St. Louis commanding the Union Army’s Department of the Missouri. It was Halleck who directed Lieber to Mound City and to his son Hamilton.
The old acquaintances quickly struck up a renewed correspondence, for Halleck found himself in need of Lieber’s expertise. Halleck was an engineer trained in the orthodox West Point style. His views of war rested on the rational geometry and engineering axioms that dominated the Academy’s antebellum curriculum, not on the rule-defying art of the Prussian Clausewitz. Clausewitz had emphasized the irreducibly contingent and probabilistic character of war. But Halleck had entered the war believing with Jomini and against Clausewitz that “war is not, as some seem to suppose, a mere game of chance.” War, he had written, constituted “one of the most intricate of modern sciences.” The general who understood how to apply its rules and principles, Halleck thought confidently, could “be morally certain of success.”
On the very eve of the war, Halleck wrote a long book that adopted a similarly tidy view of the legal rules governing warfare. The book, titled International Law; Or, Rules Regulating the Intercourse of States in Peace and War, described a law of war that had proved capable of channeling war into fixed and durable configurations. In the laws of war at sea, he insisted, the law had “been rendered clear, definite, and stable.” The laws of war on land, he thought, had also witnessed crisp moral triumphs. Statesmen and generals alike, Halleck affirmed confidently, were “bound by rules” that governed “the conduct of hostile forces.”
Yet by early 1862, when Halleck was reunited with Lieber in St. Louis, the aging engineer’s confidence in the laws of war had begun to waver. In Halleck’s Missouri, the Civil War was veering rapidly away from the orderly warfare described in Jomini’s theories and in Halleck’s treatises. Indeed, after October 1861, when Major General Sterling Price and the pro-Confederate Missouri State Guard withdrew from the state, there hardly seemed to be an army to fight. Instead, bands of irregular soldiers and armed Confederate sympathizers vied with Union-allied Kansas jayhawkers and antislavery Missouri men in a bitter partisan conflict inside Union-controlled Missouri. Confederate fighters ambushed Union detachments. They struck in Sedalia and Warrensburg in the west of the state, where terrorist violence between proslavery bushwackers and free state jayhawkers had been going on ever since the savage violence of 1854 and 1855, when proslavery forces had battled abolitionists such as John Brown to decide whether neighboring Kansas would be a slave state or free. They struck in Springfield in the south of the state. They struck in Palmyra in the northeast. Union supply lines were often vulnerable to attack. But guerrilla violence aimed at defenseless civilian targets as well. Guerrillas engaged in indiscriminate violence against Union soldiers, prisoners, and civilians alike. In attacks by increasingly notorious guerrillas like Bloody Bill Anderson and William Quantrill, Union soldiers reported encountering grim evidence of mass executions and the mutilation of bodies.
Guerrillas such as the infamous William Quantrill harassed Union sympathizers in and around Missouri from 1861 onward. Here Harper’s Weekly depicts Quantrill’s raid on Lawrence, Kansas, in 1863.
As Union forces began to occupy substantial parts of the South, irregular warfare became more widespread. The influential southern magazine De Bow’s Review had supported partisan-style warfare from the outset of the conflict, and now its editors urged that the South abandon “all fastidious notions of military etiquette” and expel the Union “by every means.” Irregular bands sprang up in western Virginia and eastern Tennessee in the fall of 1861 and in the rest of Tennessee by February 1862. By April, they were appearing in and around Union-occupied New Orleans and in northern Louisiana and Arkansas. By the early summer, Union incursions into northern Alabama and Mississippi occasioned the formation of irregular self-defense companies there too. Later in the summer, guerrilla units rose in eastern North Carolina in and around New Bern. Everywhere Union soldiers went, citizens who seemed loyal Unionists by day turned into Confederate irregulars by night.
In the spring of 1862, the leadership of the Confederacy decided to authorize and expand the irregular effort. In April, the Confederate Congress enacted the Partisan Ranger Act, which authorized Jefferson Davis to commission officers to form “bands of partisan rangers” who were to be in the service of the Confederacy, paid by the Confederacy, and subject to “the same regulations as other soldiers” in the Confederate armies. Similar calls for guerrilla units followed quickly in places like Arkansas and Missouri. Statesmen like Davis and General Robert E. Lee had been reluctant to adopt partisan warfare. Such men had been critical of guerrilla warfare in Mexico a little more than a decade before. But Union occupation of substantial parts of the South left them with little choice. Davis in particular hoped that putting the irregular bands of local defenders on an official footing would make such groups more effectively controllable from Richmond. But very soon such hopes proved unwarranted.
Southern expansion of the irregular war efforts produced new cycles of violence. Prominent southerners talked wildly of mounting irregular invasions of the North that would devastate civilian resources; Edmund Ruffin of Virginia urged that guerrillas “might lay waste to Philadelphia with fire and sword, or lay Cincinnati & even Chicago in ashes.” And for a while, it looked as if Ruffin’s terrible dream might come true. For virtually the entire month of July 1862, John Morgan’s brigade raided north past Union lines into Kentucky, nearly reaching Cincinnati, and disrupting Union operations the whole way. The expansion of irregular forces also occasioned a sharp rise in indiscriminate violence. More cautious observers than Ruffin worried that Confederate guerrillas were turning out to be “robbers and jayhawkers” who competed with Union troops in “plundering, devouring and wasting the subsistence of loyal Southerners.” Confederate brigadier general J. O. Shelby in Arkansas condemned the irregulars who served in his district as having “no organization, no concentration, no discipline, no law, no anything.”
On the other side, Union soldiers in southern territory began to act as U.S. troops had in Mexico in 1847. Already in 1861, the proslavery Missouri Republican decried the “hurricane violence” of Union reprisals that had shed “the blood of friends and kindred” throughout the state. Halleck complained to Secretary of War Edwin Stanton about Kansas jayhawkers (“robbers,” Halleck called them) who wore Union uniforms and received Union pay, but whose “principal occupation for the last six months seems to have been the stealing of negroes, the robbing of houses, and the burning of barns, grain, and forage.” In northern Alabama, Union forces under Major General Ormsby M. Mitchel burned the town of Paint Rock in retaliation for guerrilla attacks on Union transport trains. That same month, May 1862, Colonel John Basil Turchin—a former Russian army officer who had served the czar in the Crimean War—allowed his troops to sack the town of Athens, Alabama, in retaliation for civilian participation in a Confederate cavalry attack. In September, William Tecumseh Sherman ordered the burning of Randolph, Tennessee, after guerrillas fired on an unarmed Union mail steamer there. When his regiment returned from torching the town, Sherman simply reported to his commander that Randolph was gone.
CAUGHT IN THE maelstrom of irregular warfare, Union commanders cast about desperately for solutions. As early as August 1861, Major General John C. Frémont (Halleck’s predecessor in Missouri) declared martial law and announced that he would execute“all persons who shall be taken with arms in their hands” within Union lines. In December, Halleck ordered the same treatment for persons “not commissioned or enlisted” in the Confederate service; they would be tried as criminals, for it was a “well-established principle” that only those men “duly enrolled in the service of an acknowledged enemy” were entitled to prisoner of war status. “Insurgents and marauding, predatory, and guerrilla bands” were “not entitled to this exemption” from the criminal laws. Such men, by the laws of war, were “regarded as no more or less than murderers, robbers, and thieves,” and nothing in their “military garb” or their assumed company name could “change the character of their offenses” or “exempt them from punishment.”
Halleck’s position in late 1861 and January 1862 drew on the orthodox view of who counted as a soldier. For more than a century, the law of who was entitled to fight in war had been simple: the duly authorized soldiers of sovereign states were entitled to go to war. The English jurist William Oke Manning stated the basic rule in 1839 when he wrote that legal violence in war was “only allowed” by those who were “expressly authorized” to act “by the sovereign power.” The German Georg Friedrich von Martens had said the same thing a few decades earlier. The Swiss Vattel wrote that only “a commission from their sovereign” afforded men “such treatment as is given to prisoners taken in regular warfare.” And on the eve of the Civil War, Theodore Dwight Woolsey, the president of Yale College, said that the laws of war offered no protection to those who fought “without a sanction from their governments.” Halleck’s own book, International Law, adopted the same rule: “partizan and guerrilla troops” who fought without “commissions or enlistments,” he wrote, were not entitled to the privileges of the laws of war; when they were “authorized and employed by the state,” however, “they become a portion of its troops.”
It was no wonder, then, that in the winter 1861–62, Halleck distinguished between those men who were “commissioned or enlisted” in the Confederate Army, on one hand, and self-organized guerrilla bands, on the other. But the official Confederate embrace of partisan rangers in the spring of 1862 revealed a potential flaw in the orthodox Enlightenment approach. For what the Confederacy had shown in the Partisan Ranger Act was that a belligerent could very easily extend commissions to irregulars and thus give them the status of soldiers deserving prisoner of war treatment. Moreover, a belligerent could do so without changing the behavior of the irregulars at all. Halleck’s own book had suggested—indeed, it had stated clearly—that commission or enlistment was the key criterion. But now this view seemed impossibly naive. Merely issuing “commissions or licenses” to the bandits who terrorized the state, he now reasoned, ought not change their legal status. “You must be aware, general,” he wrote reprovingly to his Confederate counterpart Sterling Price, “that no orders of yours can save from punishment spies, marauders, robbers, incendiaries, guerrilla bands, etc., who violate the laws of war.” Halleck’s conclusion was firm: “You cannot give immunity to crime.”
Price replied that his men were “specially appointed” and instructed to act in accordance with “the laws of warfare.” In Arkansas, Confederate general Thomas C. Hindman likewise insisted that official recognition transformed criminal guerrillas into legal soldiers. His irregulars, he told Union colonel Graham N. Fitch, were “recognized by me . . . as Confederate troops,” and Hindman asserted “as indisputable” his right “to dispose and use those troops” as he saw fit. “We cannot be expected to allow our enemies to decide for us,” complained another Confederate general later in the year, “whether we shall fight them in masses or individually, in uniform, without uniform, openly or from ambush.”
The problem of the partisan rangers sprang up in western Virginia, too, where Governor John Letcher argued that all those “acting under the authority” of Virginia, “with commissions issued in pursuance of law and under the seal of the State,” were entitled to protection as soldiers and prisoners of war. Confederate secretary of war George Randolph agreed and fiercely defended the partisan rangers against the accusation that they were not soldiers entitled to the protections afforded to soldiers. The stakes were very real. For if the Union were to execute men carrying Confederate commissions, the Confederacy would retaliate in kind against Union soldiers in Confederate custody.
EVEN AS THE controversy over guerrilla warfare was heating up, Matty and Francis Lieber received heartrending news from Virginia. In late June they learned that their oldest son, Oscar, had been killed while fighting for the South in the Battle of Williamsburg. “Civil war,” Lieber wrote to his rediscovered friend Halleck, “has thus knocked very loudly at our door.”
Personal tragedy notwithstanding, Lieber’s importance in the Lincoln administration was growing. Behind the scenes in 1861 he had helped to organize the administration’s defense of its suspensions of the writ of habeas corpus. Now, in the summer of 1862, President Lincoln and Secretary of War Stanton promoted Lieber’s friend Halleck to general-in-chief of the Union armies. Halleck and Stanton began to call on Lieber to solicit his advice on some of the most difficult questions of the war effort.
As one of his very first acts as general-in-chief, Halleck asked Lieber to prepare a formal memorandum of the international laws of war governing the guerrilla controversy. Lieber threw himself into the task, and in a week’s time, he sent Halleck a long essay entitled Guerrilla Parties Considered with Reference to the Laws and Usages of War. Halleck liked it. (“I highly approve,” he told Lieber.) Before the month was over, the general-in-chief had ordered 5,000 copies for distribution in the Union armies. The document would help guide Union policy toward irregular fighters until the end of the war.
Halleck could be enthusiastic about Guerrilla Parties because Lieber’s treatment neatly solved the problem of the commissioned irregular by reorganizing the law of combatants. In Mexico, Winfield Scott’s councils of war had treated the soldier in a guerrilla unit as a special kind of criminal. Halleck and Lieber were now asking who was a soldier in the first place. And Lieber’s answer went beyond the formal question of whether a band of fighters was commissioned by a legitimate belligerent. Instead, Lieber asked himself what were the working characteristics that made men soldiers. The regular soldier, Lieber decided, was defined by a number of different features. The soldier typically served in a regular army. He was usually paid and provisioned by that army, which eliminated the imperative to engage in pillage. His band was permanent (or at least durable) in its formation. His movements were dictated by a central command structure that enforced discipline over him and his comrades. He wore the garb of a soldier, or at least some badge of his status, in a way that distinguished him from the peaceful citizen. He followed the laws of war and took prisoners when his enemy surrendered.
For Lieber, the formal existence or absence of a commission from a state (or as he put it, whether a band of fighting men was “self-constituted”) was relevant to, but not determinative of, soldier status. Echoing Halleck’s letters to Price, Lieber wrote that it could not be “maintained in good faith” that an armed prowler or bushwacker would “be entitled to the protection of the law of war” simply because “his government or his chief has issued a proclamation” authorizing such violence. Instead, determining whether a fighter qualified as a soldier required careful consideration of the relevant criteria in light of the underlying goals of the laws of war: uniforms or badges that separated fighters from civilians; an organized command structure that could enforce discipline and the rules of combat; and the institutional capacity to take and keep prisoners.
Commentators would later criticize Lieber’s guerrillas paper as verbose and rambling. There is something to the criticism, to be sure. Lieber was prone to long-windedness, and the paper (whose readership was made up of hard-pressed officers in the field) ran to 6,000 words. It provided lavish historical examples that ranged from the Greek Civil War to Napoleon’s Peninsular Campaign, from the ancient world to the sixteenth-century Dutch revolt against the Spanish. It lingered on Lieber’s beloved Prussian resistance to Napoleon and it reviewed at great length obscure European treatments of the laws of war. The paper, in short, engaged its topic as a philosophical problem as much as a military imperative.
But if Lieber’s Guerrilla Parties paper was wordy, that was so in substantial part because it forged new ground. Lieber’s new criteria were linked together by a common thread. Each of them substituted functional considerations for the formal question of whether a fighter had been commissioned by one of the warring sides. Clausewitz had described the formal customs of eighteenth-century war as an artifact of relations among the states of Europe. Now, in a new political context in which war was being fought outside the confines of nation-states, the simple structure of those customs no longer seemed adequate to commanders like Halleck. Lieber grasped that war had overflowed its eighteenth-century political constraints, and that in the sprawling and disorganized wars of the modern age, the laws of war would need reorganization.
The innovation Clausewitz inspired and Lieber made in August 1862 is still in our law today. We can see it in the Third Geneva Convention of 1949, which defines the soldier by reference to the considerations Lieber’s essay first raised.10 And it influenced the practice of Civil War commanders as well. Within weeks of its drafting, the approach Lieber adopted for Halleck made its way back to the western theater. In September 1862, when William Tecumseh Sherman denied that Confederate guerrillas were entitled to prisoner of war treatment, he cited the arguments that Lieber and Halleck had articulated a month earlier. “Whether the guerrillas or partisan rangers, without uniform, without organization except on paper, wandering about the country plundering friend and foe, firing on unarmed boats filled with women and children” were “entitled to the protection and amenities of civilized warfare,” Sherman wrote drily to his Confederate counterpart Thomas Hindman, “is a question which I think you would settle very quickly in the abstract.”
Even if Lieber’s analysis of the irregular warfare problem was influential, it was hardly definitive. It left wide discretion in the hands of officers in the field. One of the most striking features of Union treatment of guerrilla fighters for the rest of the war was its variability from region to region and command to command. Some Union soldiers and statesmen, from line infantrymen to officials in the War Department and right up to the attorney general of the United States, favored summary field executions for guerrillas—executions that left precious little time for close inquiry into who qualified as a soldier and who did not. Lieber did not reject such executions out of hand. (“The most disciplined soldiers,” he wrote, “will execute on the spot an armed and murderous prowler found where he could have no business as a peaceful citizen.”) But he was cautious in endorsing a harsh policy of field executions for fear that doing so risked a vicious spiral of retaliation. Other Union officers adopted military commissions on the model of General Winfield Scott’s in Mexico. And some officers even worked to find ways to treat guerrillas as prisoners of war when the situation so warranted.
Lieber’s great success was to establish a new functional basis for Union treatment of Confederate irregulars, one that the Confederacy came to accept, if only grudgingly. Lieber’s approach treated many of the partisan rangers commissioned under the April 1862 Confederate legislation as legitimate soldiers, but distinguished those who fought without outward badges of identification, without organized command structures, or without adherence to the basic laws of war.
Abraham Lincoln shared Lieber’s tough humanitarianism. He tacitly approved the policy of death sentences for guerrillas, a policy that was discussed in the cabinet. Yet time and again he commuted such sentences to imprisonment at hard labor for the duration of the war. Aggressive soldiers sometimes arranged for summary executions precisely to avoid the lengthy delays that inevitably accompanied Lincoln’s formal military commissions process.
IN FRANCIS LIEBER’S study on 34th Street in New York (just steps from where the Empire State Building now stands), a tablet on the mantelpiece displayed the names of every soldier who had fought at Fort Donelson in his son Hamilton’s 9th Illinois. With the 9th Illinois looking down on him, Lieber’s message to Halleck and Sumner and Lincoln—indeed, to virtually anyone who would listen—never varied. Lieber encouraged Lincoln and his administration to wage what Clausewitz had described as “war in earnest.” Such a war eschewed many of the constraints of limited eighteenth-century warfare, for too often those constraints seemed to Lieber to have little application to the great struggle of North and South for the future of civilization in North America. War, as Lieber saw it, was no trifling matter to be constrained by mawkish social conventions. It was the forward motion of civilization. “Blood,” he wrote Halleck, “is occasionally the rich dew of history.”
What made the Civil War an epochal event in Western history, according to Lieber, was what he saw as its underlying cause. The war pitted a free people against slavery. As summer turned into fall in 1862, slavery took center stage in the war. Lincoln and Stanton and Halleck would soon require answers to the new set of problems that Emancipation raised.